1. Field of the Invention
The present invention relates to an optical device and an optical pickup device employing the optical device.
2. Description of the Prior Art
An optical pickup device for reading data or information written on an optical recording medium such as an optical disk includes a semiconductor laser as a light source, a lens for collimating a light emitted from the semiconductor laser, an objective for creating a light spot on the optical recording medium, and a light receiving element for sensing a light which is reflected on the recording medium and which is attained via the objective. Furthermore, the device includes depending on a focusing error detection method and a tracking error detection method employed therein various optical devices such as a grating, a polarization light beam splitter, and a cylindrical lens. Since the optical pickup device is constituted with a combination of these various optical elements, an assembly operation including an optical axis adjustment is considerably complicated.